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D. A. MILLER sTovE PIPE SEAN VNov. 3, 1931.

Filed April 5, 1927 Patented Nov. 3,V

UNITED sine-res PATENT OFFICE DONALD A. MILLER, F lNEW PHILADELPHIA,OHIO, .-ASSIGNOR TO THE REEVES MANU- FACTUBING COMPANY, 0F DOVER, OHIO,L CORPORATION 0F OHIO l srovr. :PIPE am Application med April 5, 1927.Serial No. 181,252.

This invention relates to stove pipes and particularly to the seam orjoint whereby the free edges of a sheet of metal forming the pipe areconnected. D; The general object of this inventlon 1s to provide meansfor interlocking one margin lof'the sheet' with the other. This generalobject has been accomplished by a 'stove pi e on the market where theseam is formed y 1o folding one edge of the pipe section and insert,-ing the other edge' or margin lnto the groove or fold thus formed. yThis seam, however, is open to the objection that the outer wall of thegroove is formed of two thicknesses of metal, these two thicknessesbeing apertured for engagement by a boss or button formed upon the othermargin of the section or sheet. This renders the seam unsightly becausethe aperture and the boss are both disposed upon the exterior of thepipe. Furthermore the button or boss is disposed so close to the freeedge of the metal and must be so deep in order to pass through the twothicknesses of metal forming the outer wall of the groove, that themetal is likely to break or tear away at these buttons under strain.Again, in this form of seam, pressure tending to compress the pipe intoa somewhat elliptical cross section is likely to disengage the seam, orin other words, disengage the button from the opening in which it isinterlocked. Furthermore, while the two margins are held against straintendingto pull them apart, yet they may be quite readily shiftedlongitudinally on each other under pressure which will cause the buttonsor protuberances to slip out of engagement with the apertures and thestove pipe becomes disengaged. y

The speciic object of my invention is, l',therei:'ore, to improve uponthe construction above described by forming a seam in which theinterlock is entirely concealed on the interior of the pipe; in whichthere can be no tearing out of the slots nor of the buttons orprotuberances and in which, once the device is locked, there can be nodetachment of the parts without the use of tools and considerableeffort.

My invention is illustrated in the accompanying drawings, wherein Figure1 is an elevation of a stove pipel gon-structed in accordance with my`invenion.

Figure 2 is a vface view of the seam of the stove pipe looking towardthe inside face thereof.

.Figure 3 is a like view of the parts, but with the two margins of thepipe separated.

F1gure4 is a detailed section on the line 4-4 of Figure 2.

Figure 5 is a transverse section on the line 5--5 of Figure 2.

Figure 6 is a sectional view on the line of Fi re 3.

F1gure is an enlarged sectional view through the boss on the same lineas Figure 5, but to show the overhanging of the boss.

Referring to these drawings, 1() designates a sect1on of a stove pipehaving the usual circular shape when the edges or margins arelnterlocked, this section of pipe being formed of a sheet of metal bentin a circular form and having its margins interlocked as w 1ll be laterdescribed. One end of the-stove plpe section 10 is contracted so that itmay enter the adjacent end of another stove pipe. This 1s a commonconstruction and, of course, does not form part of my invention. Onemargin 11 of the metal forming part of the stove plpe section 10 isinwardly bent upon itself as at 12 and then again refolded and extendedlongitudinally as at 13, thus defining between the walls 12 and 13 thegroovev 14 into which the margin 15 of the sheet metal forming the stovepipe section is to be inserted. The folds or flanges 12 and 13 aredisposed upon'the inner face of the pipe section. The iange 13 has atspaced intervals apertures 16. These apertures are approximatelysegmental and intersect the fold or bend at the inner margin of theflange 13.

Thus these apertures open away from the outer edge of the flange 13. Themargin 15 is formed at intervals with protuberances or bosses 17 whichare approximately semicircular in form and are struck out from thevsheet metal so as to provide, as shown in Figures 4 and 5, therelatively sharp corners or steeply angled peripheral sides 18. It willbe seen i that not only is lthelinetlal each or butbut that the endsofthe boss-lor button e face, adjacent the edge offthe'inetalinar'e alsoformed with this steep sidejfajce and that the outer face of the boss isthe ed e of the metal. y 0

Wit this construction, when the margin is inserted intothe oove or s ace14, the bosses orbuttons 17 'wi l'act to li the ange ton formed with arelativelysteep sid 13 until the bosses or buttons are sprung into placein the apertures 16. When this occurs, the two margins are interlockedwith eac'h other and cannot become unlocked unless the flange 13 isdeliberately lifted away from the Han ev or fold 12 .so as to disengagethe -bosses 1 from the apertures 16 an tion to the other marginwillcause the disen- I' preferably the peripheral vas shown in Figure 7 soas gagement of the interlock. This cannot take place with myconstruction and the interlock secured between the buttons 17 and theapertures 16 will hold the pipe against any such deformation.Furthermore with this con-` struction a` compression of the pipe fromthe outside which would tendto make it elliptical in cross section willcause the inter-l lock to be even more'effective as it will tend toforce the protuberances 17 inward with relation -to the iian e 13,whereas with the construction hereto ore described as on the market, acompression -of this kind tends to disengage the interlock between thetwo inargiiis of the pipe section. Furthermore, inasmuch as the buttonsand apertures are on theinside of the pipe, they are not4 visible andthe pipe has a-much better appearance.

l'clinedslightly` towardl fitting vthe aperture,

. to confront t e any ull in any direction' from detaunent ofthe parts.

I claim v 1. A stove pipe section comprising a metallic sheet, onemargin of which is folded causing the' rearward fiat against the insideof the sheet Y and then refol ed to form a flan e s aced from butparallel to the first name fol and defining a groove2 said flange being,apertured between'the unction -of the ange with the first named foldand theedge of the ange, each aperture having a curved edge extendingfrom the junction of the flan and fold, the other margin of the sheetbein "inserti-I ble into said groove d formed with a boss ahe boss beingformed ripheral arcuate face adapted arcuate edge of the aperture, theupper face of the boss being inclinedtoward the edge and inner face ofthe sheet.

2.. A stove pipe. section comprising armetallic sheet, one 'margin ofwhich is folded rearward flat against the inside face of the sheet andthen -refolded lspaced from but parallel to the 4first named fold anddefining a groove', said flange being formed with a segmental apertureintersectwith a Steep named fold, the 'curved edge of the segmentalaperture extending toward th edge of the gange, the other margin of themetal sheet eing tersecting theedge o the sheet and fitting saidaperture, the being'steeply ang ed throu hout itsl entire extent and theouter face oft e boss being inclined inward and toward the edge of thesheet. 4

In vtestimony whereof I affix my si DONALD A. MIL

ature. ER.-

Another advantage of myv construction is v that the raw edge whichdefines the aperture 16 is confronted by the circumferential face `ofthe corresponding protuberance and one raw edge does not come against orbearA against another raw edge. Where this occurs the edges are liableto cut each other. and the metal of the sections be torn away or becomebroken at this point. While I do not wish to edge or wall of theslightly re-entrant n to more thoroughby interlock with the wall of theopening 16 than it otherwise would do, so as to prevent bo'ss orprotuberance 17 ,is

be limited to this,

eripheral edge ofthe boss I to form a iiange .ing the junction of theange with the first l insertible'into said groove and formed with anapproximate] semicircularboss in- 'les

